Napoleon called short sellers "enemies of the state." Others believe they serve a useful purpose.
One thing that bubbles have in common? The unpredictable consequences of economy-wide innovations.
Neil Irwin of The New York Times discusses the "laziest, simplest approach" to investing and says aspects of populism have long influenced the markets.
Companies can try to capitalize on a spike in stock prices by issuing new stock while the price is high.
Individual investors are apparently fueling the increase. It's a similar strategy to what we've seen with GameStop stock.
Hedge fund traders were quick to call foul when Redditors banded together to drive up the price of GameStop stock. But it was probably perfectly legal.
After shares of the video game retailer closed down 44% Thursday, they were up about 80% at market open Friday.
Some small day traders don't mind losing a little if it means hedge funds lose a lot.